Two consumer advocacy groups on Monday urged Bridgestone/Firestone Inc. to immediately broaden its recall of tires said to have been linked to at least 46 highway deaths.

"The additional tires that should be recalled are the 15-inch Wilderness AT tires from the three other Firestone plants and all 16-inch tires," Joan Claybrook, president of Washington D.C.-based Public Citizen, told a press conference.

Last week, Bridgestone Corp. announced the recall of 6.5 million tires made by its U.S. unit, namely the 15-inch Firestone radial ATX and radial ATX II tires, as well as the 15-inch Wilderness AT tires, all three brands manufactured at Firestone's Decatur, Ill. plant.

Firestone's three other plants that make the Wilderness AT tires are located in South Carolina, North Carolina and Quebec, a spokesman at Public Citizen said.